Human teeth are stained by adhesion of various staining substances on their surfaces along with calculus and plaque, and the gloss of teeth also decreases. These staining and decrease in gloss are not cosmetically desirable, and various means to whiten teeth are developed.
It has been known that phytic acid has activities such as removal of tobacco tar, a suppressive effect against calculus and stabilization of stannous fluoride, and a cleansing agent and a dentifrice, each containing phytic acid, have been reported (Patent Document 1). A dentifrice composition in which a tin compound (Patent Document 2), zeolite (Patent Document 3), particles having specific collapse strength (Patent Document 4) or the like is mixed along with phytic acid has been also reported. Further, the present applicant reported that although minute solid matter with the height of less than 1 μm which adhere to a tooth surface cannot be sufficiently removed with conventional whitening agents or abrasives, minute solid matter which adheres to a tooth surface can be removed by using a composition which contains phytic acid and no polyvalent cation and having pH adjusted to a certain range, the tooth can be whitened and gloss can be imparted to the tooth (Patent Document 5).